As a coating method for forming a coat on a sheet-like substrate, a bar-coating method has been widely used because its simple structure and operation enable a high-speed coating.
This method is a method in which a coating liquid is supplied onto a sheet-like substrate to form a coat while controlling its thickness by means of a coating bar. The coat thus formed is converted, by hardening (for example, by curing), to a coating film to be used.
However, recently, a sheet-like substrate having a coating film formed thereon is widely used for various purposes, and there is a growing demand for a coating film having a more uniform film thickness. By making the thickness of the coat more uniform, a coating film having a more uniform film thickness is obtained.
As to the bar-coating method, for example the following methods are proposed for making the coat more uniform: a method in which a coating liquid of which amount is at least 1.1 times more than an amount of the coating liquid to be coated is supplied so that the coating liquid is flown toward both sides of a web from its center (see Patent Document 1 below); and a method in which a coating liquid held in a liquid dam is stirred in the case wherein the coating liquid contains sedimentary particles (see patent Document 2 below).
Although unevenness in the coat thickness is reduced by these methods, a simple coating method for forming a coat on a sheet-like substrate, which coat has a less unevenness in the coat thickness, is still desired.    Patent Document 1:
Japanese Patent Kokai Publication No. 2003-053234A    Patent Document 2:
Japanese Patent Kokai Publication No. 2003-170104A